Material-This Cat water fountain filter is made of non-woven fabrics, active carbon, and Ion-exchange resin. Use-Filter out hair, sediment and debris and improve the taste of water so that your pets can drink clean and fresh water from cat fountain. Easy to replace: Please replace the filters for 2- 4 weeks and clean the fountain periodically. Compatible-The filter compatible with clear pet fountain/cat fountain, please confirm the size before purchase. Customer service-We stand behind our product, please contact us if you have any question, we will solve your problem in 24 hours.